Preserve the current state
Take file and database backups before changing themes, plugins, credentials or server configuration. Keep a record of the time, symptoms and recent changes. A backup is useful only when you know how it will be restored.
Find the actual failure
Check application logs, server logs, recent updates, user accounts, scheduled tasks and database changes. A visible error may be the result of a deeper security, resource or compatibility problem.
Repair in controlled steps
Change one layer at a time and verify the important business journeys after every major step: homepage, login, enquiry, checkout, email and mobile use. Avoid replacing half the system when one component is responsible.
Close the route back in
A clean page does not prove a clean website. Remove unauthorised access, rotate credentials, update vulnerable components, review permissions and confirm that malicious scheduled jobs or database entries are gone.
Leave a useful handover
The business team should know what failed, what was changed, what remains risky and what should happen next. Technical work creates more value when it reduces future uncertainty.